Wittig reaction in benzene-aqueous alkaline solution

Tagaki, Waichiro; Inoue, Isao; Yano, Yumihiko; Okonogi, Tsuneo

doi:10.1016/s0040-4039(01)92300-7

Cited by 57 publications

(17 citation statements)

References 6 publications

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“…Togaki and coworkers [22] examined the PTC Wittig reaction conditions in detail for obtaining of the maximum yield of ole¯n. In a series of experiments, increasing the NaOH concentration increases the yield of ole¯ns (Reaction 5).…”

Section: Methodsmentioning

confidence: 99%

Wittig and Wittig-Horner reactions under phase transfer catalysis conditions

et al. 2003

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Wittig and Wittig-Horner reactions are favorite tools in preparative organic chemistry. These ole nation methods enjoy widespread and recognition because of their simplicity, convenience, and e¯ciency. Phase transfer catalysis (PTC) is a very important method in synthetic organic chemistry having many advantages over conventional, homogenous reaction procedures. In this paper, we attempt to summarize the aspects concerning Wittig and Wittig-Horner reactions that take place under phase transfer catalysis conditions.

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Section: Methodsmentioning

confidence: 99%

Wittig and Wittig-Horner reactions under phase transfer catalysis conditions

et al. 2003

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“…Also like the results discussed in the above section, relief by the application of PTC method has been partially fulfilled. For the Wittig reaction, the use of aqueous NaOH as base is successful for aldehydes [Markl, 1973;Hunig, 1974;Tagaki, 1974].…”

Section: Condensationsmentioning

confidence: 99%

Phase Transfer Reactions

Ho¹

1998

Distinctive Techniques for Organic Synthesis

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Chemical reactions involving two or more molecules usually proceed at higher rates in one phase. However, it is not always feasible or expedient to render some reactions under homogeneous conditions. In such cases the phase transfer technique should be considered. Improvement of reactions by phase transfer catalysis (PTC) represents a breakthrough in chemical technology. Although sporadic reports appeared before the 1960s, consolidation of the concept through a series of publications on the theme of extractive alkylation [Markosza, 1965], a patent describing catalysis of heterogeneous reactions [Starks, 1968], and the observations concerning reactions of quaternary ammonium salts in nonpolar media [Brandstrom, 1969[Brandstrom, , 1972 initiated an avalanche of research in the methodology.While the most common phase transfer technique deals with reactants in two immiscible liquids, its scope encompasses gas-liquid, gas-solid, liquid-solid, and presumably solid-solid systems. In comparison with conventional methods, PTC holds considerable advantages in terms of cost (which avoids expensive anhydrous dipolar aprotic solvents), time, mildness, and simplicity. It is often observed that reactivities and selectivities are enhanced under such conditions.From an electrochemical study [Tan, 1994] of the Williamson ether synthesis under phase transfer catalysis, it is concluded that the role of the catalyst is to establish a Galvani distribution potential difference between the two phases which acts as the driving force for transferring the reactive ions from the aqueous medium to the organic layer.The general features of a typical PTC substitution reaction carried out in a system of organic and aqueous phases specifies reaction taking place in the organic layer. The phase transfer agent is present in catalytic amount and capable of moving one reactant in its resident solvent into that of the other reactant or the interfacial region. Only then the two species can react with reasonable speed. Needless to say that strong agitation is a most crucial to maximize reaction rates.Actually there are two mechanistic models for the PTC reaction. In the Starks extraction mechanism the catalyst is biphilic, thus well qualified by a quaternary ammonium or phosphonium salt, either of which having finite solubility in both phases on account of its charge and organophilicity, capable of ferrying the counter anion from the aqueous phase to the organic layer by the partition phenomenon. The 1 Distinctive Techniques for Organic Synthesis Downloaded from www.worldscientific.com by PURDUE UNIVERSITY on 04/13/15. For personal use only.2 Distinctive Techniques for Organic Synthesis anion generated from reaction will pair with the quaternary onium species and enter the aqueous phase and a second catalytic cycle starts at this point. The interfacial mechanism (proposed by Makosza and modified by Brandstrom and Montanari) describes cases in which the catalyst is highly organophilic and it functions by anion exchange in the interfacial region. In ot...

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“…This mixture was then converted by the action 1,. nARAD1Cs et nl., Synthesis of 7(E), 9(Z)-Dodecadien-1-pl Acetate of triphenyl-brom-phosphoniurn bromide into the broino derivative 11 + 12, which on subsequent quaternization with triphenylphosphine [5] gave selectively the phosphonium salt 13, due to the reactivity difference between the two halo compounds (Scheme 4). Wittig olefination was utilized to build up the B(%) double bond under phase transfer catalytic conditions [6] (Scheme 5 ) . Since compound 13 is a reactive phosphoniurn salt, 0.5 N sodinm hydroxide was found to he suitable enough to generate the ylerie 14.…”

Section: I-c4h8mentioning

confidence: 99%

Exo‐ and endohormones. XII. Synthesis of 7(E),9(Z)‐Dodecadien‐1‐yl Acetate, the sex pheromone of european grape vine moth Lobesia botrana, involving phase transfer technique

Daradics¹,

Oprean²,

Hodosan³

et al. 1987

J. Prakt. Chem.

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The synthesis of 7(E), 9(Z)‐dodecadien‐1‐yl acetate using for the olefination steps Wittig and Horner reactions under phase transfer conditions is reported. The 7(E) double bond was prepared by Horner coupling of 7‐tert‐butoxy‐heptanal (1) with 0,0‐diethylphosphonoacetate (2) in a two phase system. Wittig olefination was used to build up the 9(Z) double bond by reacting 9‐tert‐butoxy‐2‐nonen‐1‐yl‐triphenyl‐phosphonium bromide(13) with propionaldehyde under phase transfer catalytic conditions.

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Wittig reaction in benzene-aqueous alkaline solution

Cited by 57 publications

References 6 publications

Wittig and Wittig-Horner reactions under phase transfer catalysis conditions

Wittig and Wittig-Horner reactions under phase transfer catalysis conditions

Phase Transfer Reactions

Exo‐ and endohormones. XII. Synthesis of 7(E),9(Z)‐Dodecadien‐1‐yl Acetate, the sex pheromone of european grape vine moth Lobesia botrana, involving phase transfer technique

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